Joe Biden became USA’s 46th president on Wednesday amid tight security arrangements. He was sworn in by the country’s Chief Justice John Roberts. Biden took the oath by laying his hands on his family’s 127-year-old Bible. 78-year-old Biden is the oldest president of the US history. Kamala Harris, 56, who was elected the first black vice-president, was sworn in by Supreme Court Judge Sonia Sotomayor. She is the 49th Vice President of the United States and the first female Vice President. Donald Trump left the White House before the swearing-in ceremony. In his absence, Vice President Mike Pence performed all the traditions.